Managing Hot Weather Risk at Work | Lessons From 1,504 UK Heat Deaths in 2025

New data from UKHSA has recorded an estimated 1,504 heat-associated deaths in England across five heat episodes during the summer of 2025, the warmest UK summer on record, with a mean temperature of 16.1°C. The figure is lower than the 3,039 modelled estimates predicted, which is encouraging. But it is still 1,504 lives, and it sits within a longer pattern: 1,311 deaths in 2024, 2,295 in 2023, and 2,985 in 2022. Heatwaves are consistently an annual workplace hazard that we must plan around.

What Does the UKHSA 2025 Data Actually Tell Us?

First, the over-85s recorded 364 heat-associated deaths per million population, with the 75–84 cohort at 116 per million. There was no statistically significant heat-associated mortality in younger age groups. That matters for any employer with an ageing workforce, an older customer base, or care responsibilities, and that is a much wider group than people often assume.

Second, the regional pattern shifted. Heat-associated deaths were predominantly observed in southern, central and eastern regions. The North East, North West, and Yorkshire and the Humber showed no statistically significant heat mortality. If your risk assessments still treat heat as a uniform UK-wide problem, the 2025 data suggests a more location-specific approach.

Third, and most significant for the safety profession: care homes saw the largest increase in heat-associated mortality compared with baseline. Hospitals and people’s own homes also saw significant rises. These are buildings we know about. We have plans, alerts, and training in place. The 2025 figures suggest those controls are still being outpaced by the conditions.

What the Law Currently Expects — and Where It’s Heading

There is no statutory maximum workplace temperature in the UK. The Workplace (Health, Safety and Welfare) Regulations 1992 require employers to maintain a “reasonable” indoor temperature, with the Approved Code of Practice setting a minimum of 16°C (or 13°C for strenuous work). The duty to assess and control heat risk sits within the Management of Health and Safety at Work Regulations 1999 and the general duty of care under the Health and Safety at Work etc. Act 1974.

That position is being challenged. The TUC continues to campaign for a statutory upper limit of 30°C (27°C for strenuous work), and a recent amendment tabled to the Employment Rights Bill would require the government to consider one. Whether or not legislation lands, the direction of travel is clear. Employers who treat heat as a serious, planned-for risk now will be a long way ahead of those who wait for the law to catch up.

Five Practical Steps Before Summer 2026

• Update your risk assessment now, not in July. Cover the six thermal comfort factors HSE sets out: air temperature, radiant temperature, humidity, air movement, clothing, and metabolic rate. Generic templates won’t cut it.
• Identify your higher-risk individuals. Older workers, pregnant employees, people on certain medications, and those with cardiovascular or respiratory conditions are not edge cases. The UKHSA mortality pattern reflects this.
• Build heat into your alert response. UKHSA’s Adverse Weather and Health Plan and the Met Office heat-health alerts give you trigger points. Tie them to your operational response: rest breaks, hydration, work scheduling, and stop-work thresholds.
• Train supervisors to spot early heat stress. Heat stroke is a medical emergency, but the warning signs — confusion, slowed responses, dizziness, cramps — are recognisable hours earlier. Spotting it in the early stages is imperative to saving lives.
• Look at PPE and dress code honestly. In hot weather, PPE designed for protection becomes a heat-stress risk in itself. Review whether lighter alternatives, ventilated options, or scheduling changes would reduce exposure without compromising the original control.

FAQs Around Heat-Related Deaths

Is There a Maximum Legal Workplace Temperature in the UK?

No. The Workplace (Health, Safety and Welfare) Regulations 1992 set a minimum of 16°C (13°C for strenuous work) but no upper limit. Employers have a general duty to maintain a “reasonable” temperature and to assess heat risk under broader health and safety legislation.

How Many Heat-Related Deaths Were Recorded in the UK in 2025?

UKHSA recorded an estimated 1,504 heat-associated deaths in England across five heat episodes during summer 2025. This was lower than the 3,039 deaths predicted by modelling, but higher than the 1,311 recorded in the cooler summer of 2024.

Who Is Most at Risk from Workplace Heat?

Older adults, people with circulatory or respiratory conditions, those on certain medications, pregnant workers, and anyone whose work involves PPE, physical exertion, or restricted access to shade and water. The UKHSA 2025 data shows mortality rising sharply from age 75 upwards.

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